Method and apparatus for parallel face finishing

ABSTRACT

1,069,174. Grinding. MICROMATIC HONE CORPORATION. Oct. 11, 1965 [Dec. 23,1 964], No. 42939/65. Heading B3D. Apparatus for finishing parallel faces of a workpiece rotatable about an axis perpendicular to the faces comprises: (a) a housing mounted for reciprocation in a plane perpendicular to the axis, the housing including at least one pair of parallel spaced longitudinally extending guide surfaces; (b) a pair of abrasive stones carried by the housing for movement therewith; and (c) means carried by the housing and movable along the guide surfaces for moving the stones into engagement with a workpiece face. The disc 14, Fig. 1, of a disc brake is supported between fixtures, one of which is rotatably supported by an adjustable hand wheel 16 and the other is carried by the shaft of an electric motor 18 serving to rotate the disc. Two opposing pairs of abrasive tool assemblies are mounted in a tool housing 23 vertically reciprocated on a fixed frame 13 by an hydraulic cylinder 15. Each tool assembly comprises an abrasive stone 33 fixed to a holder 35, Fig. 3 (not shown). Each holder has longitudinally spaced tapered rear faces 37 engaging tapered faces 39 on a plate 41 slidable in a groove in the tool housing. To advance the stone into contact with the workpiece, pressure fluid is admitted through inlet 51 and acts on a piston 43 to move the plate 41 downwards. To remove the plate 41 upwards, pressure fluid is admitted through inlet 63 and acts on a piston 55, the stone being retracted from the workpiece by leaf springs 65. In operation, the workpiece is mounted between the fixtures and the motor 18 actuated to rotate the workpiece. With the stones retracted the tool housing 23 is lowered. The stones are advanced into contact with the workpieces and the housing reciprocated rapidly to produce a random surface grain structure or slowly to produce a concentric surface grain structure. The operation may be terminated by a timer or by a gauging device. In a modification. Fig. 7 (not shown), the tool housing 23 is reciprocated through a connecting rod 75 by a crank-pin 77 on a disc 73 driven by a variable speed motor. The workpiece 14 is raised into finishing position by a lift 83 hydraulically or otherwise actuated, and having a concavity 85 to cradle the workpiece. One fixture 87 is reciprocable by a fluid motor 89 or a hand wheel and has a tapered end portion 91 engaging a central opening 93 in the workpiece to raise it clear of the lift and press it into engagement with the other fixture. The workpieces may be handled automatically.

July 22, 1969 A. s. CZUBAK ETAL METHOD AND APPARATUS FOR PARALLEL FACE FINISHING Original Filed Dec. 23, 1964 5 Sheets-Sheet 1 NVENTORs ji -L 3 Sheets-Sheet 2 A 1? klf A 9 7701mm 1 I A. S. CZUBAK ETAL METHOD AND APPARATUS FOR PARALLEL FACE FINISHING M @J H. m i 4 5 f 9/ Original Filed Dec. 23, 1964 3+ i fi July 22, 1969 July 22, 1969 A. S. CZUBAK ETAL Original Filed Dec. 23, 1964 3 Sheets-Sheet 5 United States Patent 3,456,402 METHOD AND APPARATUS FOR PARALLEL FACE FINISHING Albin S. Czubak, Detroit, and Robert W. Militzer, Huntington Woods, Mich., assignors to Micromatic Hone Corporation, Detroit, Mich., a corporation of Michigan Original application Dec. 23, 1964, Ser. No. 420,751, now Patent No. 3,333,366, dated Aug. 1, 1967. Divided and this application Feb. 20, 1967, Ser. No. 659,240

Int. Cl. B24b 1/00, 7/02 U.S. Cl. 51-326 3 Claims ABSTRACT OF THE DISCLOSURE A machine and method for abrading flat annular surfaces on the opposite sides of a member capable of being rotated. An example of such a member is a brake disk. The disk is rotated about a fixed axis while an abrasive supporting housing is reciprocated in a plane perpendicular to the rotary axis. Abrasive stone carried by the housing are biased against the opposite sides of the disk. By varying the rate of rotation of the disk and the stroke and rate of rotation of the housing various surface finish patterns can be produced on the disk.

This is a division of application Ser. No. 420,751, filed Dec. 23, 1964, now United States Patent No. 3,333,366.

This invention relates to abrading methods and devices, and particularly to an improved method and apparatus for finishing parallel faces of particular workpieces.

In machining work faces of some workpieces, it is important that these surfaces be finished flat and to a high degree of parallelism. An example of this type workpiece is the disc of a disc brake assembly. Such a disc has a pair of outwardly facing parallel annular flat faces which are engaged by brake pads. The flatness and parallelism of these faces must be established to a high degree of accuracy in the finishing operation; otherwise, uneven braking forces would be experienced in use and these faces would be subject to uneven wear and the useful life of the brake materially shortened. It is also important in finishing the parallel faces on rotatable workpieces like the above disc-type brakes that the finished faces be accurately designed perpendicular to the workpiece rotational axis. Otherwise, the brake shoes would be caused to wobble and apply uneven braking forces, reducing braking efficiency and subjecting the brake assembly to high fatigue stresses.

The present invention deals with a method and apparatus adapted to finish work faces of this type to a high degree of accuracy. Briefly, the invention includes an improved abrading tool housing and tool guiding assembly of relatively simple but sturdy construction adapted to finish work surfaces to a high degree of accuracy as to flatness and parallelism, as Well as to provide the work surfaces with a highly accurate surface finish, finish pattern and dimension control. A frame is provided which rigidly supports the workpiece adjacent the tool housing and may be adapted to rotate the workpiece about its central axis. The abrading tool assembly is adapted to move transversely of the workpiece rotational axis whereupon abrasive tools provided thereon are displaced relative to the tool assembly into contact with the parallel faces of the workpiece. Thus, by then rotating the workpiece about its central axis and engaging the work face with abrasive tools, the parallel faces will be accurately finished. In use, the tool assembly is reciprocated at a controlled rate in a plane disposed perpendicular to the workpiece rotational axis while the workpiece undergoes rotation. In this way. the finished work faces may be designed to possess a variety of surface grain contour. After the finishing operation is completed, the tools are retracted from the workpiece and the tool assembly withdrawn.

It is an object therefore of the present invention to provide an improved method and apparatus capable of establishing a high degree of flatness and parallelism on finished faces of a workpiece.

It is a further object of the present invention to provide an improved method and apparatus capable of establishing a high degree of flatness and parallelism on finished faces of a workpiece.

It is a further object of the present invention to provide an improved method and apparatus of the above type wherein the finished faces of the workpiece are accurately dimensioned and perpendicular to a central axis therethrough and have an accurately controlled surface finish.

It is a further object of the present invention to provide an abrading tool assembly of the above type having an improved tool guiding assembly.

It is a further object of the present invention to provide an abrading tool assembly of the above type movable into and out of a work engaging position as a unit.

It is a further object of the present invention to provide an abrading tool assembly of the above type adapted to be reciprocated at a controlled rate during the abrading operation.

It is a further object of the present invention to provide an abrading method and apparatus capable of providing a variety of surface finish patterns.

It is a further object of the present invention to provide an abrading tool assembly of the above type which is relatively inexpensive to manufacture, rugged in construction and reliable in operation.

Further objects and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings in which:

FIGURE 1 is a perspective view of a honing machine embodying the principles of the present invention;

FIG. 2 is an enlarged fragmentary View of the structure of FIG. 1 showing the abrading tool assembly of the present invention at the upper and lower reciprocatory limits of its abrading movement as illustrated by the full dot-dash lines, respectively;

FIG. 3 is a sectional view of the structure of FIG. 2 taken along the line 3-3 thereof;

FIG. 4 is an end view of the structure of FIG. 2 taken in the direction of the arrow 4;

FIG. 5 is an enlarged view of a workpiece showing one type of surface grain structure attainable with the device of the present invention;

FIG. 6 is an enlarged View of a workpiece showing another type of surface grain structure attainable with the device of the prevent invention; and

FIG. 7 is a view similar to FIG. 1 showing a modified form of tool housing drive.

Referring now more specifically to the drawings, FIG. 1 illustrates a honing machine which is seen to include a base 11 to which an upright frame 13 is suitably affixed. A fixture frame 12 is suitably supported upon the base 11 and is adapted to support and position a workpiece during the finishing operation. In the illustrated embodiment, a workpiece consisting of a conventional disc-type automotive brake 14 is supported between suitable fixture (not shown), one of which may be rotatably supported by an adjustable hand wheel 16 and the other carried by the output shaft (not shown) of an electric motor 18. Both the hand wheel and motor are supported upon the fixture frame 12 and these fixtures are of a conventional type which will rigidly support the workpiece for rotation and are readily fixed thereto. Thus, rotation of the output shaft of motor 18 will, through the fixtures, impart rotation to the workpiece about its central axis.

A hydraulic cylinder 15 is suitably fixed to frame 13 and has disposed therein a piston 17 for vertical movement relative thereto. A suitable source of hydraulic fluid may be supplied to the cylinder in the usual manner by a means (not shown) to cause vertical reciprocation of the piston. An adapter 19 may be formed integral with the lower end of piston 17 and is provided with a pair of flanges 21 at its lower end. A tool housing 23 is provided at its upper end with a pair of retainers 25 each of which snugly receives a respective one of flanges 21. Thus, the tool housing will reciprocate vertically with piston 17.

Each rear side edge of the tool housing is formed with an elongated notch 27, each of which slidably receives a guide rail 29 suitably carried by and fixed to frame 13. Each of these guide rails is snugly but slidably retained within its respective notch by a retainer plate 31 suitably fixed to the rear of the tool housing. Thus, movement of the tool housing will be accurately controlled by the guide rails.

Disposed within the tool housing for movement therewith are a plurality of abrasive tool assemblies each consisting of an abrasive stone 33 fixed to a stone holder 35. While the number of these tool assemblies provided may vary by choice, for finishing the disc-type brake illustrated, two opposing pairs of stones and stone holders are used. Each of the stone holders shown is provided with a plurality of longitudinally spaced identical tapered faces 37 at its rear edge positioned to engage complementary tapered faces 39 formed on each of four expander plates 41. As shown, these expander plates are closely but slidably retained each within a longitudinally extending groove 42 formed in the tool housing by a plurality of retainer plates 44 suitably fixed thereto. By carefully machining the longitudinal surfaces of these expander plates and grooves 42 in which they slide, and by maintaining .a close sliding relationship therebetween, the abrasive stones will be maintained in accurate parallelism with themselves and each other when moved into contact with the workpiece and the Work faces finished accordingly.

A plurality of primary pistons 43 are each positioned within a corresponding primary cylinder 45 formed within the tool housing and are adapted for vertical reciprocating movement relative thereto. Each of the primary pistons is operatively connected to a respective one of expander plates 41 by suitable means such as a pin 47 to thereby impart corresponding reciprocatory movement thereto and each of the pistons is provided with a conventional O-ring 48 to sealingly engage the wall of cylinders 45. An end cap 49 is suitably attached atop tool housing 23 to close the ends of primary cylinders 45 and is provided with a plurality of inlet openings 51 adapted to threadedly receive fluid conduits 53. Thus, as fluid is supplied under pressure to each conduit 53 in a conventional manner, downward movement will be imparted to pistons 43 and therefore to expander plates 41. This will in turn cause movement of each of the tool assemblies inwardly toward the workpiece, by engagement between tapered faces 37 and 39 on the tool holders and expander plates, respectively, until the tools engage workpiece 14.

To retract the tool assemblies outwardly away from the workpiece at the conclusion of the finishing operation, a plurality of secondary pistons 55 are provided and each has one end disposed for vertical movement within a plurality of secondary cylinders 57 formed in housing 23, while the other end of each of the secondary pistons abuts the lower end of a respective one of the primary pistons. Each of pistons 55 carries a conventional O-ring 59 which sealingly engages the wall of the corresponding cylinder 57 while a plurality of fluid conduits 61 are suitably connected to cylinders 57 at openings 63 to supply hydraulic fluid thereto. Thus, upon completion of the honing operation, the pressure on fluid to conduits 53 may be released and fluid under pressure may be supplied by conduits 61 to the secondary cylinders. This will move pistons 55, and therefore pistons 43, upwardly with tapered faces 39 on the expander plates moving away from faces 37 on the stone holders. A suitable means, such as leaf springs 65 fixed to the tool housing with one end of each engaging a respective end of each stone holder 35, will then move each of the tool assemblies outwardly away from the workpiece.

As shown, the tool housing is movable from a position completely above and away from the workpiece (FIG. 1), to a position where the workpiece is received within a longitudinal opening 67 formed therein (FIG. 3), and is adapted to be cycled reciprocally at a controlled rate througha finishing stroke illustrated by the full line and dot-dash positions shown in FIG. 2 by controlling the rate of flow of fluid to cylinder 15. Also, the tool assemblies are movable from a position retracted from the workpiece (not shown) to a position where stones 33 engage the workpiece (FIG. 3) by suitably controlling the flow of fluid to cylinders 45 and 57. While the details of these controls, including a suitable fluid source, pumps, and valves have not been illustrated, it is to be understood that the same will be of a conventional nature and within the realm of the skilled hydraulics engineer. The fluid system provided will be controlled from suitable control panel 69 mounted upon the machine frame.

In the operation of this machine, the workpiece is mounted between the fixtures carried by hand wheel assembly 16 and motor 18 and the motor is actuated to rotate the workpiece. With the tool assemblies in their retracted positions, which can be accomplished by n0rmally maintaining fluid under pressure to openings 63 of cylinders 57 and exhausting fluid from cylinders 45, fluid is supplied to cylinder 15 to move piston 17 downwardly. Thereafter, fluid is supplied to cylinders 45 by conduits 53 and is exhausted from cylinders 57 by conduits 61 thereby moving stones 33 into engagement with workpiece 14. Depending upon the surface grain structure desired on the workpiece, the tool housing will then be reciprocated at a fast rate of travel, through a preselected stroke, one example of which is indicated by the full line and dot-dash positions of FIG. 2, or the tool housing will reciprocate through this stroke at a reduced rate of travel. In the former, a random type surface grain structure or lay pattern, as illustrated by FIG. 6, will be formed on the workpiece by the rapid rate of relative longitudinal movement between the stones and workpiece during the finishing operation. In the latter, a concentric lay pattern, as illustrated in FIG. 5, is formed since a reduced of relative longitudinal movement takes place between the stones and workpiece. Thus, the resulting surface grain structure may be varied according to customer desires.

After completion of the abrading operation, which may be determined by either a timer or by a suitable gauging device, fluid is exhausted from the primary cylinders and is supplied to the secondary cylinders with springs 65 retracting the tool assemblies, whereupon fluid may be supplied to cylinder 15 to move piston 17 upwardly and the finished workpiece removed from the fixtures.

FIG. 7 illustrates a modified form of reciprocating drive means for the tool housing and workpiece positioningmeans. This structure is, in all other respects, substantially identical to that of FIG. 1 and like numerals indicate identical parts.

Thus, a drive motor (not shown) is fixed to the frame 13 and is provided with a rotary output shaft 71 having a crank disc 73 fixed thereto adjacent the end thereof. A connecting rod 75 is pivotally connected at one end to the disc 73 by a pin 77 and at its other end by a pin 81 to a spaced pair of cars 7-9 fixed to the tool housing 23. The pin 77 is disposed eccentrically of the disc 73 so that rotation of the disc by the drive motor (not shown) causes the tool housing to reciprocate vertically. As in the device of FIG. 1, the tool housing 23 is guided by guide rails 29 fixed to the frame 13.

The tool housing drive means of FIG. 7 is energized to reciprocate the tool housing 23 at a rapid rate when it is desired to form a random type surface grain structure or lay pattern, as illustrated by FIG. 6 and described above in the device of FIG. 1. Conversely, this tool housing drive means reciprocates the tool housing 23 at a relatively slow rate when it is desired to form a concentric lay pattern shown in FIG. 5 and also described above. This variable rate of tool housing reciprocation is achieved by using a variable speed drive motor to drive the crank 73.

In the device of FIG. 1, the tool assembly was moved adjacent and retracted from the workpiece 14 by supplying fluid to the cylinder 15 to move the piston 17. In the device of FIG. 7, the workpiece 14 is raised into position in preparation for the finishing operation by a movable lift 83 which is hydraulically or otherwise suitably actuated. As shown, the lift 83 is formed concave as at 85 to cradle the workpiece 1 4 and is moved upwardly to raise the workpiece 14 to a position adjacent the rotatable fixtures one of which is shown at 87. The fixture 87 is reciprocable, as by a fluid motor 89 or by a hand wheel as shown in FIG. 1, and is extended to grip the workpiece 14. For handling the disc brake 14 shown, the fixture 87 has a tapered end portion 91 positionable within an opening 93 centrally of the workpiece 14 to raise it slightly from the lift 83 and press it into engagement with the other fixture (not shown) whereupon the motor 18 which drives the fixtures is energized. Thereafter, the tool assemblies are moved into engagement with the workpiece 14 and the finishing process is carried out as described above. Upon completion of the finishing process, the tool assemblies are retracted and the lift 83 lowered. The finished workpiece is removed and a new workpiece 14 is placed on the lift cradle surface 85 in preparation for the next finishing process.

The lift device 83 can be motivated by any suitable drive means such as a fluid motor. In addition, the workpieces 14 can be manually placed on and removed from the cradle surface 85 or they can be handled automatically as desired. In addition, suitable guide means may be provided to prevent the workpiece 14 from falling off the lift 83 during its raising and lowering sequence.

Thus, by the present invention there has been provided an abrading device for finishing parallel faces on a workpiece which will form fiat finished faces accurately parallel to each other and perpendicular to the workpiece axis of rotation.

While preferred embodiments of the present invention have been illustrated and described in detail, various additions, substitutions, modifications and omissions may be made thereto without departing from the spirit of invention as encompassed by the appended claims.

What is claimed is:

1. A method of finishing fiat annular parallel faces on the opposite sides of a workpiece comprising the steps of rotating said workpiece about an axis perpendicular to said parallel faces,

moving a finishing tool holder transversely of said rotational axis adjacent said workpiece,

and moving a pair of parallel finishing tools disposed on said holder relative thereto and toward one another into engagement with said parallel faces of said workpiece.

2. A method of finishing parallel faces of a workpiece comprising the steps of rotating said workpiece about an axis perpendicular to said parallel faces,

moving a finishing tool holder transversely of said rotational axis adjacent said workpiece,

moving a pair of parallel finishing tools disposed on said holder relative thereto and into engagement with said parallel faces of said workpiece,

and controllably reciprocating said tool holder transversely of said workpiece rotational axis while said tools are in engagement with said parallel faces.

3. A methodof finishing parallel faces of a workpiece comprising the steps of rotating said workpiece about an axis perpendicular to said parallel faces,

moving said workpiece transversely of said rotational axis and adjacent a finishing tool holder,

moving a pair of parallel finishing tools disposed on said holder relative thereto and into engagement with said parallel faces of said workpiece,

and reciprocating said tool holder transversely of said workpiece rotational axis while said tools are in engagement with said parallel faces.

References Cited UNITED STATES PATENTS 2,807,916 10/1957 Squire et al 51-42 X JAMES L. JONES, JR., Primary Examiner 

